The present invention relates to an intro-play method for a compact disk graphic player in which playback of one program and jumping ahead to a succeeding program are alternately and repeatedly performed, and more particularly, to an intro-play method in which the proceeding to a subsequent program is prevented until the playback of graphics information related thereto is completed.
A compact disk recording/reproducing method is one in which binary information is recorded as a plurality of pits on a 12cm radius disk and the binary information is reproduced by irradiating a high-quality light such as a laser and reading out the intensity of the reflected light. Such a compact disk recording/reproducing method includes a compact disk (CD) mode for recording only audio information, a compact disk video (CDV) mode for recording audio and video (moving picture) information, and a compact disk graphics (CDG) mode for recording audio information along with still picture graphics information.
The present invention deals with an intro-play method for the CDG mode in which the information of a still picture is recorded in addition to the audio information.
A compact disk has, starting from the edge of the disk and moving radially inwards towards the center, a lead-out area, a program area and a lead-in area. A music signal is recorded in the program area the range of which is from 50mm to 116mm away from the center of the disk along the radius. The lead-out area contains a signal indicative of the end of a program. The lead-out signal which is a repetition pulse of 2Hz is recorded from the end point of the program area ( 116mm from the center of the disk along its radius) to 117 mm.
The lead-in area contains the number of pieces of music recorded on the disk, the performance time of the respective pieces of music, the overall performance time of the pieces of music, and the start address of the respective pieces of music. The lead-in area is called the table of contents (TOC). The TOC area begins from about 46mm away from the disk center to just before 50 mm, which is the start position of the program, along the radius of the compact disk of 120mm radius. In the TOC area, TOC signals are repeatedly recorded.
An intro-play method has been proposed which involves searching the recorded pieces of music using the various information recorded in the TOC area.
The intro-play function involves repeatedly performing an operation of reproducing a program recorded on the compact disk from the starting point thereof for a predetermined period (e.g., ten seconds) and then jumping to a succeeding program.
During the intro-play operation, the compact disk player reproduces the first recorded program from the initial point thereof for a predetermined period while referring to the TOC of the compact disk, and then shifts the optical pickup to the location of the second program so as to reproduce it. This operation is repeated until a user inputs a release instruction or a final program is reproduced.
When such an intro-play function is employed in a compact disk graphic player, since the "intro" playback time (e.g., ten seconds) assigned to the respective programs is constant, the switching of the recorded programs is not performed smoothly with respect to the switching among stored graphics images. For instance, if the playback time assigned to the respective programs is shorter than the time required for the graphics information related to a given program to be read out and displayed, the graphics image stops being displayed during its output and display onto a monitor (an operation which proceeds from the upper left to the lower right of the screen), and the image related to a succeeding program to be reproduced is then overwritten on the monitor starting from the upper left. Ultimately, the changing of the pictures is not smooth and is offensive to the human eye.